Rational Assembly of d10 Metal−Organic Frameworks with Helical Nanochannels Based on Flexible V-Shaped Ligand

Solvothermal reactions of Zn(II) or Cd(II) nitrates and V-shaped ligand of 4,4′-(hexafluoroisopropylidene)bis(benzoic acid) (H 2 hfipbb) in the presence or absence of 4,4′-bipy afforded four interesting d 10 metal−organic frameworks with helical nanochannels, namely, Zn(hfipbb)·0.5H 2 O·0.5DMF enantiomers ( P 6 2 22, 1a, and P 6 4 22, 1b ), Zn(hfipbb)(4,4′-bipy)·DMF ( 2 ), and Cd(hfipbb)(DMF)·0.5DMF ( 3 ). The enantiomeric 1a and 1b exhibit similarly a (4,4)-connected 3D network with two types of helically 2-fold and 8-fold nanochannels along the c -axis, in which ultralong helical pitches are found in the 8-fold helical channels. Compound 2 features a 2D layered structure based on dizinc(II) paddle-wheel clusters with the appearance of left- and right-hand helical channels alternatively, while 1D double helical channels exist in the complicated structure of compound 3 . The luminescent properties of all the compounds have also been studied.